Add a built-in status-line item with reset countdowns

Title: Add a quota-summary built-in status-line item with reset countdowns

Summary

Please consider adding a new built-in TUI status-line item, quota-summary, that renders the 5-hour and weekly quota remaining percentages together with reset countdowns.

Example output:

5h:87%(2h1m) wk:50%(5d22h)

Problem

The existing built-in limit items expose remaining percentages, but not the countdown-to-reset signal.

For users who rely on Codex for scheduling and dispatch decisions, the reset countdown is the important missing piece. Remaining percentage alone is not enough to decide whether it is safe to start a high-throughput or long-running task.

This matters especially for:

• deciding whether to dispatch a coordinated team workflow
• deciding whether to start a long-running debugging/refactor session
• reducing unnecessary context switching to other tools just to inspect reset windows

Proposed Design

Add a new built-in status-line item:

• quota-summary

Behavior:

• additive only; do not change existing five-hour-limit or weekly-limit semantics
• render short-form quota remaining plus reset countdown
• omit unavailable windows instead of rendering placeholders

Suggested format:

• 5h:87%(2h1m) wk:50%(5d22h)

This keeps the current status-line architecture intact:

• one new built-in item
• one shared formatter for quota-summary display
• existing items remain backward-compatible

Why This Shape

I am not asking for a full custom multi-line HUD or a Claude-style footer clone here.

A single additive built-in item is much lower risk:

• no change to existing item semantics
• small surface area for maintenance
• easy to document and test
• useful immediately for scheduling decisions

Notes on Scope

This proposal intentionally does not require:

• arbitrary custom footer rendering
• multi-line footer layout
• custom progress-bar glyph rendering

Those are larger UI/design questions. This request is specifically about exposing the reset countdown signal in the existing status-line system.

Verification from a Local Prototype

I implemented this locally as an additive quota-summary item in the TUI and verified:

• config/setup picker support
• runtime status-line rendering
• countdown formatting from existing rate-limit reset timestamps

Targeted verification used:

cargo test -p codex-tui --lib quota_summary -- --nocapture

Why It Seems Aligned

The existing status-line system already has:

• a fixed built-in item enum
• rate-limit data in TUI state
• existing 5-hour and weekly limit items

So this seems like a natural additive extension rather than a new subsystem.

If this direction is aligned with the team’s intended solution, I already have a working branch and can provide details or a patch outline in the issue discussion.